"And be it further enacted, that in case the original inventor or discoverer of the art, machine or improvement for which a patent is solicited is a slave, the master of such slave may take an oath that the said slave was the original; and on complying with the requisites of the law shall receive a patent for said discovery or invention, and have all the rights to which a patentee is entitled by law."[17] The national ban on patents for the inventions of slaves did not, of course, attach itself to the inventions made by "free persons of color" residing in this country. So that when James Forten, of Philadelphia, who lived from 1766 to 1842, perfected a new device for handling sails, he had no difficulty in obtaining a patent for his invention, nor in deriving from it comfortable financial support for himself and family during the remainder of his life. This was also true in the case of Norbert Rillieux, a colored Creole of Louisiana. In 1846 he invented and patented a vacuum pan which in its day revolutionized to a large extent the then known method of refining sugar. This invention with others which he also patented are known to have aided very materially in developing the sugar industry of Louisiana. Rillieux was a machinist and an engineer of fine reputation in his native State, and displayed remarkable talent for scientific work on a large scale. Among his other known achievements was the development of a practicable scheme for a system of sewerage for the city of New Orleans, but he here met his handicap of color through the refusal of the authorities to accord to him such an honor as would be evidenced by the acceptance and adoption of his plan.[18] Who knows but that the city of New Orleans might have been able to write a different chapter in the history of its health statistics on the Yellow Fever peril if its prejudices had not been allowed to dominate its prophecy? [Illustration: _N. Rillieux_ _Evaporating Pan._ _No. 4,879_ _Patented Dec. 10, 1846_ _Sheet 3-4 Sheets_]